Dual fluid cartridges are used to store and dispense two fluids which must be kept separate until the time of use and then, at the time of dispensing, need to be mixed together very quickly in a precise pre-set ratio to ensure that the proper chemical reaction takes place. If the cartridge does not dispense the two fluids properly in the required pre-set ratio, the final fluid mixture may be greatly affected and may not function or adhere as required. Examples of such fluids are those that are used to create thermoset adhesives (i.e., a resin and a hardener).
Dual fluid cartridges have been used in industry for a long time and, over the years, differing types of dual fluid cartridges have been developed. An example of a relatively recently developed dual fluid cartridge is the one depicted and described in U.S. Pat. No. 5,310,091, entitled “Dual Product Dispenser”. The dual fluid cartridge depicted and described in the '091 patent is an effective dual fluid cartridge. It can be filled relatively easily and can be used in readily available dispensers, such as caulking guns. With fluids that need to be combined in a 1:1 ratio, the dual fluid cartridge of the '091 patent is especially effective. The dual fluid cartridge of the '091 patent may also be used with fluids that need to be combined in a non-1:1 ratio (e.g. 2:1 ratio). However, when the ratio of the two fluids that need to be combined starts to deviate from 1:1, the dual fluid cartridge of the '091 patent becomes less effective. Because the dual fluid cartridge of the '091 patent only has two chambers to hold fluid, as the ratio between the two fluids that need to be stored and dispensed increases, the space wasted in the cartridge increases and the amount of final product that can be produced decreases. At high ratios (e.g. a 10:1 ratio), the space wasted within the cartridge and the reduction in final product that can be produced becomes significant.
Accordingly, there is a need for a dual fluid cartridge that is effective in storing and dispensing fluids in unequal ratios such that there is minimal wasted space in the cartridge and the total final product capable of being dispensed is maximized.